Fuel pump control module

[frank_ster]

well its pwm so heat sink does not need to be large. or even nessasary

[SeeeeeYa]

well its pwm so heat sink does not need to be large. or even nessasary

 

19 amps is 19 amps, however it's driven.

[frank_ster]

uh ? no it depends on how waste full the circuit is made..

[mwiener2]

There has to be heat to sink

[SeeeeeYa]

uh ? no it depends on how waste full the circuit is made..

 

There has to be heat to sink

 

 

Short and complete.

 

Explains the little sealed boxes.

[KCwagon]

Here are some better pics. The heatsink is on the backside of the module.......So I guess there is heat to sink.

 

http://i573.photobucket.com/albums/ss178/shoneal55esp/DSC00105_zpse09500ec.jpg

 

 

http://i573.photobucket.com/albums/ss178/shoneal55esp/DSC00104_zpsccbf1723.jpg

http://i573.photobucket.com/albums/ss178/shoneal55esp/DSC00106_zps00f3f663.jpg

Edited February 6, 2013 by KCwagon

[Drew888]

 

Why do you need me to keep proving you are overloading the FPCM? They are failing on you!

 

I'm electrically inept. That said this seems too simple in concept and I'm having difficulties understanding where Mwiener is coming from unless he lost something in the thread because he didn't read it all the way through ( I did).

 

Overly simplified, all that is being shown is that the LGT's lacks what the STI has. We mod to specs similar to the STI using like parts. Now the only variable left seems to be the FPCM. Once upgraded our hardware mirrors the STI.

 

They are using oem parts. What's the issue? Is it because they are upgrading wiring beyond the OEM spec of the STI which potentially could provide the FPCM with more current? If so then limit the gauge of wire and call it a day.

 

Scooby2.5, I apreciate your efforts! There is only a learning opportunity when something interesting is discovered. I'd think that if you aren't having fueling issues then it's a moot point but if you are and can lower IDC's because of this then fantastic.

Edited February 7, 2013 by Drew888

[KCwagon]

More reading.......

 

http://forums.nasioc.com/forums/showthread.php?t=2308392

[Scooby2.5]

Ok KCwagon and I worked on his car today and got no where.

 

We did find that the PWM signal on the FPCM is switching the ground reference voltage from 0 to various voltages to get the 10v for 67% and 8v to get 33%.

 

So what is happening is you are feeding say 14v to the pump and the negative lead from the module to the pump is changing voltage.

 

In the thread KC Wagon posted above (359) read posts 7, 10, 17, 20 Most of them by Z0rr0

 

He wired direct battery voltage to the pump and then left the module negative side from the module to the pump alone.

 

This would provide full voltage to the pump and allow the module to just change the negative reverence point from 0 to 4 to 6 giving you a difference of 14 for 100%, 10 for 67%, 6 for 33% for the different duty cycles. (approx voltage numbers)

 

His car has been running fine.

 

After the low voltage discovery on my car Calvin from Cobb and myself wired it the way we did but probably shouldnt have.

 

Looks like the stock FPCM would work fine the way Z0rr0 has done it.

 

This way you are not trying to push HIGHER voltage THROUGH the FPCM. Although the STI wiring is larger so sends higher voltage to the module from the fuel pump relay

 

And the only thing changing is the lower voltage on the negative side from the module

 

 

I put in a call to him already and will report back after we chat about it.

Edited February 7, 2013 by Scooby2.5

[KCwagon]

Question: Does anyone know for sure what the FPCM references to determine the pump duty ? (33,67,100)

 

I read in another thread here on LGT.com that it was the crank position sensor.

[frank_ster]

^ crank posetion sensor? i dont think so,

 

from what i have seen its not rpm related its more engine load related but i dont know for sure.

[Scooby2.5]

http://www.myo-p.com/PWM%20Motor%20Controller.pdf

[Scooby2.5]

i didnt read the whole thread.

 

the pwm for the fuelpump is on the negative only. so if ou ground the ground on the pump the pump will start with the key. ie when the key is in ing position the pump will always run

 

Which seems to mean that z0rr0 is correct. Run BAT voltage direct to the fuel pump. Leave the Negative wire from the module to the pump and you should have a good PWM signal.

 

Sound right to you Frank?

[Scooby2.5]

I would find it really hard to believe the stock controller and wiring could support the walbro 400.

 

I would take a direct 12GA or 10GA wire from the battery. Hook that up to +12 on the pump, then use the ground from the stock controller.

 

that way, you'll have the power needed for the pump, and the safety of the controller.

 

(I had to do this in my legacy gt with the aeromotive 340)

 

 

I don't have a schemaitc. I took 10ga wire directly from the battery and hooked it to the pump +12 wire. I left the stock ground wire going to it.

 

There was no CEL or anything, its been like that for about 15k miles.

 

 

Yes, the pump followed the duty cycles. I did, however, flash the ECU to run the pump @ 100%. (only do this if you have an aftermarket regulator, the stock one will over-run, at least on my legacy)

 

I did that for other reasons, there was no problem with the pump following the PWM signal.

 

PWM is on the ground side circuit from the FPC.

Edited February 7, 2013 by Scooby2.5

[frank_ster]

Which seems to mean that z0rr0 is correct. Run BAT voltage direct to the fuel pump. Leave the Negative wire from the module to the pump and you should have a good PWM signal.

 

Sound right to you Frank?

 

 

well its easy to figure that out. check with the volt meter between chassis ground and 12v on the pump when the pump is at full load.

 

then again check on the negative of the pump to good chassis ground.

 

i would think there is voltage drop on both sides.

 

the positive side should have a large wire and a relay that is activated by the stock 12v+ feed. incase the fpcm decides to short out.

 

then the ground wire to and from the could be replaced our doubled.

 

but i suspect there is a resistor that is sized to the pump in the fpcm,

think of the fpcm as a relay that clicks on and off realy fast. but each time the relay clicks on it would ground completely then fade. so they place a capacitor ( shock absorber ) to slow the fade but the resistor ( spring ) to give the capacitor a chance to charge. so putting a big pump is like putting a bob cat in the back of a s-10 pickup. where the springs are now way under sized.

[KCwagon]

^ crank posetion sensor? i dont think so,

 

from what i have seen its not rpm related its more engine load related but i dont know for sure.

 

That is why I asked. I am sure it is not RPM based. Maybe a MAP sensor reference or a combination of references.

Edited February 7, 2013 by KCwagon

[Scooby2.5]

well its easy to figure that out. check with the volt meter between chassis ground and 12v on the pump when the pump is at full load.

 

then again check on the negative of the pump to good chassis ground.

 

i would think there is voltage drop on both sides.

 

the positive side should have a large wire and a relay that is activated by the stock 12v+ feed. incase the fpcm decides to short out.

 

then the ground wire to and from the could be replaced our doubled.

 

but i suspect there is a resistor that is sized to the pump in the fpcm,

think of the fpcm as a relay that clicks on and off realy fast. but each time the relay clicks on it would ground completely then fade. so they place a capacitor ( shock absorber ) to slow the fade but the resistor ( spring ) to give the capacitor a chance to charge. so putting a big pump is like putting a bob cat in the back of a s-10 pickup. where the springs are now way under sized.

 

Frank if i remember correctly thats how I finally realized how it was working.

 

On kcwagons car yesterday we would measure at the output of the module FP+ and FP- What we found was the voltage would obviously change based on the requested duty cycle.

 

When it went to 33 percent or 67 percent and I would measure from FP+ to the chassis ground at the back of the car it was around 14 volts. the FP- would then be 6 volts. Difference being 8 volts.

 

So it looks like the only thing changing is the negative reference.

 

Here is a blurb from the article I posted above in regards to your last paragraph....Just information nothing more. That article does discuss the amperage of typical transistors used I think

 

With the advent of solid state electronics in the 1950’s and 1960’s and this technology becoming very affordable in the 1970’s & 80’s the use of pulse width modulation (PWM) became much more practical. The basic concept is to keep the voltage at the full value (in this case 12 volts) and simply vary the amount of time the voltage is applied to the motor windings. Most PWM circuits use large transistors to simply allow power On & Off, like a very fast switch. This sends a steady frequency of pulses into the motor windings. When full power is needed one pulse ends just as the next pulse begins, 100% modulation. At lower power settings the pulses are of shorter duration. When the pulse is On as long as it is Off, the motor is operating at 50% modulation.

Several advantages of PWM are efficiency, wider operational range and longer lived motors. All of these advantages result from keeping the voltage at full scale resulting in current being limited to a safe limit for the windings. PWM allows a very linear response

1

in motor torque even down to low PWM% without causing damage to the motor. Most motor manufacturers recommend PWM control rather than the older voltage control method.

Edited February 7, 2013 by Scooby2.5

[Scooby2.5]

I'm electrically inept. That said this seems too simple in concept and I'm having difficulties understanding where Mwiener is coming from unless he lost something in the thread because he didn't read it all the way through ( I did).

 

Overly simplified, all that is being shown is that the LGT's lacks what the STI has. We mod to specs similar to the STI using like parts. Now the only variable left seems to be the FPCM. Once upgraded our hardware mirrors the STI.

 

They are using oem parts. What's the issue? Is it because they are upgrading wiring beyond the OEM spec of the STI which potentially could provide the FPCM with more current? If so then limit the gauge of wire and call it a day.

 

Scooby2.5, I apreciate your efforts! There is only a learning opportunity when something interesting is discovered. I'd think that if you aren't having fueling issues then it's a moot point but if you are and can lower IDC's because of this then fantastic.

 

Thanks Drew, Exactly why I started doing this. At 385 WHP on E85 (30% more fuel) I was running out. We quickly and easily found it was the voltage to the pump.

Now we are trying to correct it with a stock type module instead of running the pump 100% all the time.

 

Part of the reason is the pump running all the time at 100% when not needed causes a lot of heated fuel to return to the tank from what I understand.

 

Similar STI's, I saw being tuned did NOT have the issue as the legacy.

The wiring and the module were definately different between the two cars.

 

Pretty much that is the whole story in a nut shell.

 

If it were not for 385 or more WHP on E85 it wouldn't be a problem. Pump gas tune is just fine.

 

The juice is just too much fun

Edited February 7, 2013 by Scooby2.5

[frank_ster]

the well depends on the method of the fpcm,

is it pwm 12volts and your reading 6 volts witch is the average since the meter and your eyes cant read as fast as the pwm frequency is. since its 12v then 0 volts then 12 volts again.

but this method isn't very friendly with some electric motors.

 

that being said is the capacitor on the input of the circuit to prevent noise on the rest of the system ?

[Scooby2.5]

Not sure but I have a scope so I am going to stick it on there when we work on it next time.

Ive got some pins, wiring harness etc stuff coming so I can do it factory like when we finalize it

[mwiener2]

At 385 WHP on E85 (30% more fuel) I was running out.

 

So why does my Walbro 255 with stock wiring and FPCM get me to 450+ WHP on E85 (30% more fuel)?

[Scooby2.5]

Call PHD Tim Bailey at Cobb Tuning Surgeline in Portland Oregon, maybe he can discuss it with you.

 

http://www.cobbtuning.com/Cobb-Tuning-Surgeline-s/70466.htm

[KCwagon]

So why does my Walbro 255 with stock wiring and FPCM get me to 450+ WHP on E85 (30% more fuel)?

 

Because you are better, smarter and faster than everyone else, that's why.

[mwiener2]

So no good replies?

 

 

Maybe your aeromotive is faulty... it wouldn't be the first one.

[KCwagon]

What, you didn't like my reply ? Edited February 8, 2013 by KCwagon